The present invention relates to automatic transmissions for land vehicles and, more particularly, to a universal jig/work holding fixture and reaming method for the repair of worn valve bodies and pumps of FORD MOTOR COMPANY (hereinafter “FORD”), GENERAL MOTORS (hereinafter “GM”), and other similar automatic transmissions.
Automatic transmission systems of the prior art have a hydraulic circuit subsystem which includes at least a hydraulic pump, a valve body having fluid conducting passages or circuits, input and exhaust ports formed within the fluid circuits, and a plurality of spool valves so-called because of their resemblance to sewing-thread type spools. Such spool valves are comprised of generally cylindrical pistons having control diameters or lands formed thereon, which alternately open and close the ports to fluid circuits for regulating the flow and pressure of automatic transmission fluid (hereinafter “ATF”) within the transmission.
Such spool valves must often be replaced or refurbished during service procedures due to mechanical wear. If wear is extreme the cylindrical bores in the valve body wherein such valves are located can often be machined oversize to a close tolerance to accommodate an oversize valve or a replacement valve fitted with a mating sleeve, which is installed in the oversize bore. Providing a leak proof seal between the mating surfaces of the oversize valve and/or sleeve and the valve body to prevent cross-leakage between hydraulic passages which adjoin the replacement valve is critical to salvaging a worn original equipment (hereinafter “OE”) valve body.
A significant problem is presented to the service technician in obtaining this close tolerance fit in a typical transmission repair shop using only manual tools. Thus, the present invention has been developed to resolve this problem and other shortcomings of the prior art.